Safety device for elevators.



No. 628,260. Pa'tented July 4, I899.

,U. S. ALZ.

SAFETY DEVICE FOR ELEVATORS.

(Applicntion filed In. 31, 1899.)

No Model.)

IIIIIII/II/I/I/I/II/III/A m: "cums warns on muroumo wunmu'rou. a. c.

UNITED STATES PATE T OFFICE.

URBAN S. ALZ, OF BALTIMORE, MARYLAND.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 628,260, dated July 4,1899. Application filed January 31, 1899. Serial No. 703,992. (Nomodel.)

To all whom it may concern.-

Be it known that I, URBAN S. ALZ, a citizen of the United States,residing at Baltimore, in the State of Maryland, have invented certainnew and useful Improvements in Safety De- Vices for Elevators, of whichthe following is a specification.

This invention relates to an automatic device for elevators to safelyarrest or stop the car should it accidentally fall.

The object of the invention is to provide-a simple device employing compressed air which may be applied to elevators and which will beautomatic in its operation.

In order to make the invention clearly understood, I have shown in theaccompanying drawings means for carrying the same into practical effect,without, however, intending to limit my invention to this particularconstruction, as the same may be embodied in other forms.

Figure 1 is a vertical section through an elevator-car with my improvedstop device at: tached and also shows the stationary carguides andinclined safety-ways. Fig. 2 is a horizontal section on the line 2 2 ofFig. 1. Fig. 3 is a vertical section on the line 3 3 of Fig. 2. Fig. 4is a section view on a larger scale, showing the vent-valve carried onthe car. Fig. 5 is a perspective view showing the cylinders and the pipeconnections therewith.

In the drawings, A designates the elevatorcar, movable up and down onstationary vertical guides 17 1), preferably one at each corner of theelevator-shaft. A frame 0 is secured to the car, preferably at thebottom, and said frame is provided in the present instance with twocompartments cl and e, one above the other, and a horizontal guide spaceor slot f is formed between the said two com partments by plates f f*.The upper compartment d' in the present instance contains twoair-cylinders d and d located at one end of the compartment, and thelower compartment 6 is also provided with two air-cylinders e and clocated at the opposite end. The air-cylinders have horizontal position,and each is provided with a piston g, having a stem 9, which movesloosely through the head of the cylinder, the lit of the stem throughthe head being such as to allow the free inlet and outlet ofair at thatend of the cylinder with the pistons.

whenever the piston moves. Two cross-bars h and i are horizontallymovable in the space or slot f and extend from one side to the other ofthe frame 0, and said bars at each end carry a pivoted guide-block j.The sliding cross-bar It has two studs 70, which project up throughslots Z in the upper plate f and are secured to the piston-stems of theupper cylinders d d andthesliding bar h moves The other slidingcross-bar 1 also has two studs It, which, however, project down throughslots in the lower plate f and are secured to the piston-stems of thelower cylinders e c and this bar '71 moves with said pistons.

The elevator-shaft through which the car travels is provided at oppositesides with inclined safety-ways 'm m, the lower ends of which are closetogether and which gradually diverge or spread apart as they extend up.It will be understood, of course, that the inclination of the ways m m,as shown in the drawings, is exaggerated in order to make the featureclear. As here shown, the inclined ways m m are grooved.

The pivoted guide-blocks j have position in the grooves of the inclinedways m m, and it will be seen that as the car moves up the guide-blocksj and their attached parts will move forward-that is, away from theirrespective cylindersand thepiston 9 will thereby be drawn toward thecylinder-heads, and the downward movement of the car will cause the saidguide-blocks to move in the reverse direction.

The upper air-cylinders d and d are provided with an air-pipe n, whichopens in the end of the cylinder opposite the end having thepiston-stem, and said pipe at connects with pipe 42. The lower cylinderse and e are also provided with air-pipes 0, arranged like thefirst-named pipes,which connect with the pipe 0. The pipes 0 and n areconnected, and thereby form a complete connection between all thecylinders. I

The guide-blocks j and piston g coact with the inclined guides in suchmanner that-when the car is moving downward the piston will compress theair that may be in the cylinders, and the resistance of this compressedair will gradually arrest the movement of the pistons and guide-blocks,and the car will consequently be gradually stopped. The inventiontherefore is operative without the employment of a pump; but in thepresent i11- stance I have shown an air-compressing pump P as a meresupplemental device.

In the present instance the vertical carguide Z) has a rack q, and apinion 7', which is suitably mounted on the top of the car A, mesheswith this rack. The pinion or the shaft on which it is mounted carries acrank 8. An air-compressing pump P, secured to the top of the car, has apiston and stem of ordinary construction, and a pitman 25 connects thepiston-stem with the said crank 8.

An air-pipe it connects the air-pump with the pipe n,communicating withthe cylinders under the car, and a valve '0, located in the car,controls the escape of compressed air from the cylinders and the pump.

The controlling-valve is shown in section in Fig. 4 and is to beoperated by hand; but it is obvious that it might be operated by thefoot, and the construction may be varied from that shown. In the presentinstance the valve consists of a cylinder having a piston w, and a stemprojects from the piston and has a presser-knob w. The interior of thecylinder is provided with a groove 00, and stop-lugs 3 y limit themovement of said piston.

It will be seen that when the piston to is pushed down the compressedair will escape around the piston through the groove 00, and air fromthe cylinders will thereby be released.

The objeet of employing the pump P is to aid in the compression of airin the cylinders, to the pistons of which the slide-bars andguide-blocks j are connected.

It is to be understood that the pump is intended to compress air in thecylinders both when the car is ascending and descending.

The operation of the device is as follows: Suppose the car to be at thebottom of the shaft and the guide-blocks j in the grooves of theinc'linedwaysm 112'. As the car moves upward the guide-blocks j willfollow the grooves mm, and the pistons in all the cylinders beingconnected to the guide-blocks will gradually move outward or make theirfull stroke toward the cylinder-heads. At the same time the pump P, bymeans of the rack, pinion, and pitman, will be forcing air through thepipe u to pipes n and o, and thereby charging the cylinders behind thepistons with compressed air. 1 should be so proportioned with respect tothe size of the air-cylinders that said cylinders will become filledwith compressed air when the carhas reached the top of the shaft. Thusitwill be seen that when the elevator is going up the cylinders will allbecome charged with compressed air.

In order for the car to descend, air must be discharged from behind thepistons g in order that the guide-blocks may gradually move toward thecenter vertical line, and to eilect The pump the proper discharge of theair the valve 11 has been placed in the pipe to, within easy reach ofthe person who has charge of the car. By means of this valve 'v theoperator discharges air from the pipe it, which reduces the air-pressureacting on the pistons in the cylinders, and upon such reduction ofairpressure the pistons and guide-blocks will move inward and theelevator will descend, but only as fast as the escaping air will permit.By this construction it will be seen that in-order to descend thepressure behind the pistons g mustbe released to permit the guideblocksj to move toward each other, and the discharge-groove w in the valve canbe made larger or smaller, so the discharge of compressed air may bemore or less rapid. It will thus be seen that if the cable supporting anelevator-car should break the compressed air not being able to escapefrom the cylinders would arrest the movement of the pistons and thesliding bars h t and the guide-blocks j would be held stationary in thegrooves of the inclined ways m m and the elevator thereby stopped. Theelevator-car having stopped would remain stationary until air wasdischarged at the valve 2).

\Vhile I have shown and described a pump to be used in connection withthe cylinders, it is obvious that the pump may be dispensed with andreliance placed on the atmospheric air in the cylinders and pipes.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is l 1. In a safety device for elevators thecombination of an elevator-ear movable up and down; inclined guides orways at opposite sides of the elevator-shaft; guide-blocks carried bythe ear and coactin g with the inclined guides or ways an air-cylinderprovided with a piston and a stem and carried on the car and saidpistons coacting with the guideblocks so-that normally at all times whenthe car is descending the air in the cylinder will be resisting; and avalve on the car to control the escape of air from the air-cylinderduring the ordinary descent of the car, for the purpose set forth.

2. In a safety device for elevators the combination of an elevator-carmovable up and down; stationary inclined guides or ways; air-cylinderseach having a piston and stem and carried on the car; means on the carcoacting with the inclined guides or ways; an air-pu mp carried by thecar and provided with means for establishing communication with theair-cylinders; and a valve on the car to control the escape of air fromthe cylinder to permit the earto descend, for the purpose set forth.

3. In a safety device for elevators the combination of an elevator-carmovable up and down; stationary inclined guides or ways at oppositesides of the elevator-shaft; air-cylinders mounted beneath the car onein a plane higher than theother, and each having apissaeco 3 ton andstem; horizontal plates, f, f, forming a slot or space between thehigher and lower cylinders; cross-bars movable in said slot or space andconnected with the pistonstems; and guide-blocks mounted on thecross-bars and coacting with the said inclined guides, for the purposeset forth.

4. In a safety device for elevators the combination of an elevator-carmovable up and down; stationary inclined guides or ways closer togetherat the bottom than at the top; one or more air-cylinders, each having apiston and stem; an air-pump carried by the car to charge the saidcylinders with air; guide-blocks on the car which coact with the 15pistons and the inclined guides or Ways and a valve on the car tocontrol the escape of air from the cylinders for the purpose set forth.In testimony whereof I affix my signature in the presence of twowitnesses.

URBAN S. ALZ. Witnesses:

CHARLES B. MANN, J r., GEO. KOETHER.

